48 Description of a New Species of Dipodomys. [Jan. 
hind feet comes under the centre of gravity, thus taking all the 
weight; then, often, the fore part of the body will be slightly 
raised and the fore feet drawn up against the body. If disposed 
to sleep, the bright eyes will slowly close, the fore feet droop 
until touching the ground, the nose slowly comes down and 
backward until resting between the toes of the hind feet, and the 
now sleeping animal is nearly as round as a ball. This appears 
to be the common sleeping posture. If there be room, the tail 
will be extended back nearly in'a straight line, but in cramped 
quarters it will be curved to one side or even alongside the body ; 
but in either case the basal part will be curved back enough to 
give some support. These animals make much use of the tail, 
and its loss would be a great inconvenience. When one of my 
D. deserti lost the use of its tail temporarily through its being 
frozen, I saw it fall over several times, lacking its accustomed 
support. 
I do not see them make much use of the power of scent, but 
the long whiskers are very sensitive, and must be of much use 
in their nocturnal rambles. The sight is good in daylight, though 
they do not like a strong light. If compelled to rest in a light 
place, they face away from the light if possible. Both species 
of Dipodomys seldom emerge from their burrows until the even- 
ing light gets dim. The hearing does not seem to be unusually 
acute, but I have made no experiments yet to positively deter- 
mine the fact. r ; : 
Phillips’s pocket-rat does not seem to live in companies, 
though the holes of different individuals may be but a few yards 
apart. From such information as I can gather, and from what I 
have seen myself, I think that the desert pocket-rat lives in 
colonies often if not usually. The only place where I have taken 
D. deserti has a colony of several groups of holes, each group 
being from two to eight entrances to a set of intercommunicating 
galleries, from six to thirty inches below the surface, and being 
within a space of two to three yards square. None that I opened 
proved to be inhabited. In each several galleries terminated one 
to two feet from the surface in a slight enlargement, which gen- 
erally contained the hulls of barley, etc., as if they were used as 
places of storage. Two contained a little dry grass, as if they 
_ had been used as nests. I put paper and cotton in the cages, 
but the D. deserti made but little: use of it. The D. phu 
